It is common in the trucking industry for cargo that is transported on flatbed trucks to be held down by cargo straps drawn tightly over the cargo. These straps are secured at one end to one side of the cargo bed, are drawn over the cargo, and are held tightly by a winch mounted on the other side of the cargo bed. The winch typically has a ratchet and pawl mechanism which locks the winch drum in order to retain the cargo straps in a tight condition.
One type of winch that has been used advantageously is disclosed in U.S. Pat. No. 5,490,749 to Arbues. However, the configuration of the slots through which one end of the cargo strap is threaded can cause problems. The slots in the Arbues winch drum are surrounded by edges having sharp corners that can cut or otherwise damage the cargo strap webbing. This slot configuration does not provide the winch with a strong construction, and the winch drum is thus susceptible to possible structural problems. If the drum is crushed in a collision, the slot edges can easily cut through the cargo strap. The cargo is then released, and the consequences of the collision can be greatly aggravated.
It can also be somewhat difficult to feed the strap through the slots, as the strap end can catch on the edge opposite the slot into which it is initially inserted. The strap end is often doubled over before it is thread through the drum slot. The doubled over webbing naturally tends to spread apart, and this makes it even more susceptible to catching on the slot edges.
Winch drums have also been constructed using two D-shaped sections welded together near the ends and with flat surfaces spaced apart and facing one another to provide opposite sides of the slot that receives the cargo strap. A variation of this construction involves bending the sides again to form flanges that are perpendicular to the flat surfaces on opposite sides of the slot. The primary problem with both of these constructions is that the winch drum can collapse and be crushed when subjected to heavy forces. There is no structure oriented perpendicular to the drum axis in order to provide effective resistance to crushing forces.